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What are the differences between Volovik & Wen theories?

  1. Oct 24, 2009 #1
    Both purport to make use of condense matter- models to model fundamental physics.

    What are the differences and which seems more promising?
  2. jcsd
  3. Oct 24, 2009 #2


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    I believe Wen would like emergent fermions, while Volovik wouldn't mind fundamental fermions. Neither is promising, though both are inspiring and worth studying. I think AdS/CFT is a working example for emergent gravity in some universes (not ours) that is very much in the spirit of condensed matter. So we have examples of emergent gravity (AdS/CFT) and emergent QED and QCD (Levin and Wen), but no examples of emergent chiral fermions (yet?).
    Last edited: Oct 24, 2009
  4. Oct 24, 2009 #3
    I've wondered about the relevance of AdS/CFT to our universe, esp as a fundamental theory

    Would it be possible to combine Wen's emergent QED QCD on a spin network lattice, with Bilson-Thompson braided to get emergent chiral fermions?
  5. Oct 24, 2009 #4


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    He, he - I don't know - I'd publish it if I knew :smile:
  6. Oct 24, 2009 #5
    Do spin foam spin networks have the properties with which Wen's QED QCD can emerge?

    And are "twists" in spin networks correspond to chiral fermions?
  7. Oct 24, 2009 #6
    It seems that this combination describes what Schiller is doing on http://www.motionmountain.net/research/ [Broken] In his "strand" model/conjecture, he deduces emergent chiral fermions made of braided tangles. He uses the same trick as Bilson-Thompson to show that there are only three particle generations. But Schiller predicts no Higgs - hmm...
    Last edited by a moderator: May 4, 2017
  8. Oct 24, 2009 #7
    Wen offers emergent Higgs using a local bosonic theory.

    Are neutrinos the only chiral fermions Wen is unable to account for?
    Last edited by a moderator: May 4, 2017
  9. Oct 25, 2009 #8
    That is your personal view i think Atvy, although you also know that the condensed matter physics field, is the most tested and confirmed perhaps field in physics. For me it makes sence because it ultimately also inhabits quantum mechanics as emergent. And thereby leaves out anything fundamental.
  10. Oct 25, 2009 #9


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    I guess you are disagreeing with the part where I said it's not promising? Well, these are my favourite approaches, so I say they are not promising :smile:
  11. Oct 25, 2009 #10

    Yes that's interesting Wen says fundamental particles arise from the collective behaviour of bossons. This is wat Wen exactly says.

    This paper uses a particular emergence approach: we
    try to obtain everything from a local bosonic model. The
    detail form of the bosonic model is not important. The
    important issue is how the bosons (or the spins) are organized
    in the ground state. It is shown that if bosons
    organize into a string-net condensed state, then photons,
    electrons and quarks can emerge naturally as collective
    motions of the bosons.12–15 In this paper, we will find an
    organization of bosons such that the collective motions
    of bosons lead to gravitons.


    My idea is that Volovik goes a step further then Wen, But Wen digs deeper. Although if you read Volovik's Book "the universe in helium droplet" you get a really good idea what Volovik envisions. The book goes much deeper than his papers usualy
  12. Oct 25, 2009 #11
    I infer then that for Wen bosons are fundamental, Volovik thinks fermions are fundamental. Either through string nets or emergent physics, can give rise to gauge symmetries and SM particles

    Do you know if spin networks can give rise to bosons organize into a string-net condensed state or fermions analogous to super-fluid He3?
  13. Oct 26, 2009 #12
    Volovik is presenting a high-level analogy (nasty people would call him a crackpot) whereas Wen has some original, good and promising ideas.
  14. Oct 26, 2009 #13
    So where does Group Field Theory fit in?

    Oriti offers to model spin-networks on a fat graph that gives rise to a He3 like superfluid.

    i.e arxiv.org/abs/gr-qc/0607032


    We put forward a more specific, albeit still very much tentative, proposal for the relevant phase of the GFT corresponding to the continuum: a Bose-Einstein condensate of GFT quanta. Finally, we sketch how the proposal may be realised and its effective dynamics could be extracted in the GFT setting and compared with continuum gravity theories.

  15. Oct 27, 2009 #14
    I said that Volovik's work was questionable - I have not read Oriti well enough to say something sensible about it.
  16. Oct 27, 2009 #15
    There's quite a bit of discussion about Group Field theory in LQG. But I admit I don't understand it nor know how promising it is.

    BUT if it does model spacetime as a superfluid perhaps then either or both Volvovik, Wen, or Bilson Thompson emergent schemes might be the way forward
  17. Oct 28, 2009 #16


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    Wen has an interesting diagram on the last slide of http://dao.mit.edu/~wen/talks/09Dresden.pdf

    I like the links "AdS/CFT-Emergent gravity-long range entanglement-tensor category".

    I'm trying to figure out where GFT fits in too. I think these papers indicate that something very interesting will come out of it (Thanks marcus for your biblio!).
    Freidel, Gurau, Oriti http://arxiv.org/abs/0905.3772
    Magnen, Noui, Rivasseau, Smerlak http://arxiv.org/abs/0906.5477
    Tanasa, http://arxiv.org/abs/0909.5631

    But I have nothing more than gut feeling at this point. My only indicator is sociological. Tanasa cites Markopoulou's work http://arxiv.org/abs/gr-qc/0203036 and Markopoulou has been trying to link up quantum graphity http://arxiv.org/abs/0801.0861 with Levin and Wen's work, and I'm believe this is all one coherent "sniff" on her part :smile:
    Last edited by a moderator: Apr 24, 2017
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